[time-nuts] low noise multiplication to 100 MHz

Bryan _ bpl521 at outlook.com
Tue Jan 26 21:52:57 UTC 2016

Chuck, what do you use for a hot air source. The good ones are very expensive. Wonder if there is something for the hobbyist. Have seen a few repair videos where they used just used a hot air stripper.
I had to yank a couple SMD resistors off a board the other day and had to use two soldering irons at each end of the resistor <g>. If they are small enough you can add a glob of solder to the whole resistor, so both ends will melt.


> To: time-nuts at febo.com
> From: cfharris at erols.com
> Date: Tue, 26 Jan 2016 01:50:47 -0500
> Subject: Re: [time-nuts] low noise multiplication to 100 MHz
> Hi Bert,
> I have noticed that if I have the right magnification,
> I can do amazing things.  Even the tiny age related
> tremors that naturally occur in my hands reduce with
> magnification.  The brain is a marvelous  servo mechanism.
> Get a good 40x-80x zoom stereo microscope meant for
> dissection, the type mounted on a boom, and I would bet
> you too could deal with the small surface mount parts.
> When I build with SMD, I always put all of the parts on
> the top side, and use solder paste.  I used to put lots
> of tiny dots out with a syringe that works a lot like a
> caulking gun... only smaller.  But I found that simply
> drawing a thin stripe of paste across the SMD pads
> on the board, and then setting the part on the paste,
> works just fine.  The solder draws towards the pads, and
> leaves the space between the pins clear.  Occasionally
> there will be some tiny balls sitting between the pins,
> but they clean up when I clean the board with alcohol
> and a brush...not that they hurt anything anyway.
> The chips self center while they are floating on the
> molten solder.  No need to touch them with a soldering
> iron, or anything else.
> I use a lab grade hot plate to bring the board up to reflow
> temperature.  And I am off to the races.
> For disassembly, I use an IR underboard heater, and a
> hot air source... about 1/8 inch diameter, and move it
> around the pin area until it melts, and then lift the
> part free.
> To put parts on an already populated board, I pre heat
> the underside of the board to about 1/2-2/3 the way to
> the solder melting temperature, and use a little gentle
> hot air source to head the pads the rest of the way to
> molten.  No need for soldering irons.
> Practice on junk boards until it becomes natural.
> -Chuck Harris
> Bert Kehren via time-nuts wrote:
> > We have looked at the LMK devices but with my 74 years would not try to
> > solder it. There are other neat parts out there but again who is able to
> > solder  them.
> > Bert Kehren
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